On 21 January 2014 05:01, Edgar L. Owen <[email protected]> wrote: Now the obvious effect of this (as I'm the first to have pointed out so far > as I know) is that space will necessarily be warped at the boundaries of > galaxies, and as is well know from GR any curvature of space produces > gravitational effects, and of course dark matter halos around the EDGES of > galaxies were invented to explain the otherwise unexplained extra > gravitational effects on the rotation of galaxies. >
Dark matter was first postulated (in 1932 iirc) to explain both the rotation curves of galaxies, and how galactic clusters are gravitationally bound together. So any theory of DM needs to explain both these phenomena. I believe there is also a need for DM to flatten the overall curvature of the universe (as measured by WMAP or COBE or one of those observatories). That is, the density of the universe has to be something like 4x (?) higher than is accounted for by visible "baryonic" matter, and the rest can't be baryonic because if it was, that would have changed the rates of nucleosynthesis in the big bang (there would be 4x more fuel available and the reactions would have gone a lot faster, and the universe would be a lot fuller of helium than is observed - or something like that). Hence something other than baryonic matter is needed to give the observed flatness. > > Thus, this simple effect of space warps around the boundaries of galaxies > caused by the Hubble expansion may be the explanation for the dark matter > effect. > This sounds vaguely similar to MOND - modifying the force of gravity at some boundary. (Does your theory make testable predictions that differentiate it from MOND?) > > And there is nothing to prevent these warps, once they are created, to > have a life and movement of their own, as we now know that dark matter is > not just concentrated around galactic halos but may indicate where they > used to be.... > Are you suggesting that space has a sort of memory of the curvature that was caused by the matter it *used to* contain? So for example when the galaxies in the bullet cluster collided, these warps - the imprint of the galaxies on space - got stuck together in the middle of the impact, while the visible parts of the galaxies carried on moving outwards? How would the warp get detached from the matter causing it? -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
